Abstract

Extensive studies document the effect of nanoparticles on thermal properties of fluids, such as thermal conductivity, although very few exist at subzero temperatures. The current study reports the effect of 1.4 nm palmitoyl nanogold particles (NPs) on the freezing properties of phosphate buffered saline solutions with the help of a differential scanning calorimeter. The results show that NPs have a complex effect on the two properties of interest, i.e., homogeneous nucleation temperature (Th) and phase change temperature (or the melting temperature, Tm). The homogeneous nucleation temperature was significantly elevated at a concentration of 1 nM/ml NPs with 0.167% (v/v) DMSO, and 3 nM/ml NPs with 0.50% (v/v) DMSO concentration, whereas at the other concentrations (1.2 nM/ml NPs with 0.20% DMSO, 1.5 nM/ml NPs with 0.25% DSMO, and 6 nM/ml NPs with 1% DMSO), it was significantly depressed. A similar phenomenon was also noticed in the measured values of the melting temperature of PBS solutions.

References

Figures

Shows the variation in melting point temperature (Tm) as a function of DMSO concentration at 10°C/min, 20°C/min, and 40°C/min. The % (v/v) concentration of DMSO is shown in the x-axis, while the measured value of the melting temperature (K) is shown on the y-axis.

Shows the variation in homogeneous nucleation temperature (Th) as a function of DMSO concentration at 10°C/min, 20°C/min, and 40°C/min. The % (v/v) concentration of DMSO is shown in the x-axis, while the measured value of the homogenous nucleation temperature (K) is shown on the y-axis.

Shows the variation in melting temperature (Tm) of the nanoparticle-DMSO-PBS system as a function of DMSO and nanoparticle concentration at 10°C/min, 20°C/min, and 40°C/min. The % (v/v) concentration of DMSO is shown on the bottom x-axis, while the NP concentration (nM/ml) is shown on the top x-axis. The measured value of the melting temperature (K) is shown on the y-axis.

Shows the variation in homogeneous nucleation temperature (Th) of the nanoparticle-DMSO-PBS system as a function of DMSO and nanoparticle concentration at 10°C/min, 20°C/min, and 40°C/min. The % (v/v) concentration of DMSO is shown on the bottom x-axis, while the NP concentration (nM/ml) is shown on the top x-axis. The measured value of the homogenous nucleation temperature (K) is shown on the y-axis.

Shows the effect of nanoparticles on the measured values of Tm, i.e., the difference in the measured values of Tm obtained with and without NPs is shown. The % (v/v) concentration of DMSO is shown on the bottom x-axis, while the NP concentration (nM/ml) is shown on the top x-axis. The difference in measured value of the melting temperature (K) with and without NPs is shown on the y-axis.

Shows the effect of nanoparticles on the measured values of Th, i.e., the difference in the measured values of Tm obtained with and without NPs is shown. The % (v/v) concentration of DMSO is shown on the bottom x-axis, while the NP concentration (nM/ml) is shown on the top x-axis. The difference in measured value of the homogenous nucleation temperature (K) with and without NPs is shown on the y-axis.

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